A light rail network connecting Wellington's railway station, hospital and airport and Lower Hutt is the cornerstone of a Green vision that would ditch roading projects in favour of public transport.

On a bus in Wellington yesterday, the Green Party announced it would scrap Transmission Gully, the Kapiti Expressway and the Basin Reserve flyover roading programmes and reprioritise the $2.4billion spending.

But local leaders are critical of the plan, saying the roading projects are essential for regional development.

Greens transport spokesman Gareth Hughes said the party would put more money into light rail, better bus services, and safer walking and cycling routes, and create more liveable communities.

"Around the world governments are giving people real options to leave their cars at home and that is the best way to ease congestion on the roads."

The Greens would revert to the original Western Link road for Kapiti, he said.

Party co-leader Russel Norman said the $1.2b Transmission Gully project was expensive and would not take trucks off the existing coastal highway because it would be too steep. "Wouldn't it be better to move that freight and the passenger transport on to rail rather than have it go through our communities?"

The Greens say the Government is spending $5 on new roads for every $1 it spends on alternatives but they would rebalance that to dollar for dollar.

But progressing the Greens transport plan for Wellington under a National-led government would be a "struggle", Dr Norman conceded.

Road Transport Forum spokesman Ken Shirley disputed the Greens' figures and said that over the next three years National had proposed spending $10b on roads and $7b on rail, despite roads taking 75 per cent of freight while 15 per cent of freight was moved on rail. The Greens were politicising the national highway process because of their love of other transport modes, he said.

The policy comes as a World Wildlife Fund-commissioned Colmar Brunton poll found 81 per cent of Wellingtonians believed the Government should be spending more of its transport budget on public transport.

Greater Wellington regional council chairwoman Fran Wilde agreed public transport was important, but said Wellington's roads had been neglected for too long and more than one main route in and out of the city was needed. "It's important to remember that Transmission Gully is all about route reliability ... When the sea finally reclaims Centennial Highway we need another way through State Highway 1."

Porirua Mayor Nick Leggett called the Greens' policy "madness" and said Transmission Gully and the Kapiti Expressway were essential to help develop the economic capabilities of the region. "I'm not a fan of building roads for the sake of building roads at all, but we have got some necessary and long-delayed infrastructure like Transmission Gully and the expressway that need to happen sooner rather than later."

Wellington Mayor Celia Wade-Brown's mayoral campaign was partly based on bringing light rail to Wellington. A Green Party member, she said she was on record as supporting greater emphasis on public transport. "I'm looking forward to working with the elected government and local MPs to achieve the best transport outcomes for the city".